My Inquiry
My Account
Allegro MicroSystems A8501ELPTR-T
- Part No.:
- A8501ELPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8501ELPTR-T.pdf
- Description:
- IC LED DRVR RGLTR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,465
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A8501ELPTR-T from Allegro MicroSystems is a discontinued 4-channel WLED/RGB backlight driver IC with integrated 40 V/3.6 A boost switch, 100 mA per channel current sinks, 2 MHz switching frequency, and output disconnect protection. It operates from 6.8–21 V input, supports up to 9 series LEDs per string (36 total), and targets automotive display backlighting including infotainment and cluster systems.
For engineers reviewing the A8501ELPTR-T datasheet, A8501ELPTR-T pinout, A8501ELPTR-T application, or A8501ELPTR-T equivalent, key selection considerations include its 4000:1 dimming range (PWM + DIM pin), ±0.7% LED current accuracy, thermal derating via VTI, OVP programmability up to 38 V, and 28-pin TSSOP-LP package with exposed thermal pad.
Technical Context
The A8501ELPTR-T implements a constant-frequency, current-mode boost converter with external frequency setting via FSET resistor (600 kHz–2.2 MHz). Its four matched current sinks use internal 1.235 V reference and ISET-based current programming (IISET = 1.235 V / RISET), achieving 0.7% typical accuracy and 0.8% matching across channels.
It integrates dual-stage protection: primary OVP (19.5 V default, adjustable to 38 V) and secondary SW-pin overvoltage detection for open Schottky failure; plus open/short LED detection with true output disconnect, thermal shutdown at 172°C, and 3.5 µA shutdown current for battery-sensitive applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6.8–21 V - supports 12 V automotive battery with load-dump tolerance up to 40 V transient |
| Boost Switch Rating | 40 V / 3.6 A - enables driving high-Vf LED strings while surviving automotive transients |
| LED Current per Channel | 100 mA - configurable up to 400 mA total with parallel channel tieing |
| Dimming Range | 4000:1 - 1000:1 via EN PWM + 4:1 analog scaling via DIM pin |
| Current Accuracy | ±0.7% - ensures uniform brightness across 4 LED strings in display backlighting |
| OVP Threshold | 19.5 V default, adjustable to 38 V - prevents damage during open-LED fault or capacitor failure |
| Shutdown Current | 3.5 µA - minimizes battery drain in always-on vehicle systems |
| Thermal Shutdown | 172°C typical - protects against thermal runaway in enclosed display modules |
Pinout & Package
The A8501ELPTR-T is supplied in a 28-pin TSSOP package with exposed thermal pad (suffix LP), lead-free with 100% matte-tin plating (suffix T), optimized for thermal dissipation in space-constrained automotive displays.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED1–LED4 | Current sink outputs | Each delivers regulated 100 mA; tied together support 400 mA total sink capability |
| VIN | Main power input | Accepts 6.8–21 V supply; includes UVLO (6.5 V) and OVLO (32 V) protection |
| SW (pins 4–6) | Boost switch drain | Three pins tied on PCB carry 3.6 A peak current; integrated DMOS rated 40 V |
| OUT | Output disconnect switch source | Connects to LED common cathode; opens during short/open faults to isolate strings |
| CAP | Disconnect switch gate control | Drives internal MOSFET; connects to OVP resistor network for fault sensing |
| ISET | Current reference input | Sets full-scale LED current via RISET resistor (e.g., 12.4 kΩ → 100 mA) |
| DIM | Analog dimming select | Logic-level input: low = 100% current gain (960×), high = 25% gain (240×) |
| EN | Enable & PWM input | Active-high enable; accepts 100–300 Hz PWM for precise brightness control |
| FSET | Frequency setting | Resistor to AGND sets switching frequency (e.g., 24.3 kΩ → 2 MHz) |
| VTI / VTO | Thermal derating interface | VTI accepts external NTC voltage; VTO provides 2.46 V reference for analog control |
| PGND / DGND / AGND / LGND / PAD | Ground terminals | Star-grounded multi-domain grounds: power, digital, analog, LED sink, thermal pad |
Key Features
| Feature | Design Value |
|---|---|
| True output disconnect | Hardware-isolates LED strings during open/short faults-prevents overvoltage stress on healthy channels |
| Active current sharing | 0.8% matching between LED1–LED4 ensures uniform luminance across display zones |
| Programmable OVP | External ROVP resistor adjusts threshold from 19.5 V to 38 V-enables system-level safety margin tuning |
| Thermal derating support | VTI pin accepts NTC voltage divider to reduce LED current as panel temperature rises-extends display lifetime |
| Low shutdown quiescent current | 3.5 µA at 25°C-critical for always-connected automotive modules preserving battery charge |
| Robust fault coverage | Detects and latches on open LED, shorted LED, SW overvoltage, OVP, OTP, UVLO, OVLO, and disconnect overcurrent |
Applications
| Automotive Infotainment Displays | Instrument Cluster Backlighting |
|---|---|
Use Scenario: Driving 4 parallel LED strings behind TFT LCD in center-stack head unit with variable ambient light conditions. IC Role / Device Role / Timing Role: WLED backlight driver with integrated boost, current regulation, and fault-protected output disconnect. Use Value: 4000:1 dimming range maintains readability from daylight to night; 0.7% current accuracy prevents visible banding across display zones. |
Use Scenario: Powering segmented LED backlight for analog/digital gauge cluster requiring fail-safe operation. IC Role / Device Role / Timing Role: RGB-capable driver with open/short LED detection and thermal derating for long-term reliability. Use Value: True output disconnect isolates failed string without affecting other gauges; VTI-based thermal control prevents LED color shift at high temperatures. |
| Backup Camera LCD Modules | Industrial HMI Panels |
Use Scenario: Compact rear-view camera display mounted in hot trunk environment with wide input voltage swing. IC Role / Device Role / Timing Role: High-efficiency boost LED driver with 40 V transient tolerance and 172°C thermal shutdown. Use Value: Withstands 40 V load-dump transients; 3.5 µA shutdown current avoids battery drain when vehicle is parked. |
Use Scenario: Ruggedized industrial panel with 7-inch LCD requiring ESD-hardened backlight control in factory settings. IC Role / Device Role / Timing Role: ESD-protected WLED driver (40 V HBM on LEDx/CAP/OUT pins) with latch-off fault recovery. Use Value: 40 V ESD rating on critical pins eliminates need for external TVS diodes; latched fault mode prevents uncontrolled restart after fault. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar WLED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ALT80600 | Successor device with higher efficiency, lower IQ (1.5 µA), extended temp range (–40°C to 125°C), and updated OVP architecture | Designed for new designs requiring longer product lifecycle and AEC-Q100 Grade 2 compliance | Select ALT80600 for all new designs; A8501ELPTR-T is discontinued and not recommended for new applications |
| LM3409QMY/NOPB | Standalone LED controller (no integrated current sinks); requires external MOSFETs and feedback resistors; supports up to 1.5 A | Better suited for high-current or custom topology designs where flexibility outweighs integration | Choose LM3409QMY/NOPB only if redesigning for higher current (>400 mA) or needing programmable slope compensation |
Compared with A8501ELPTR-T, ALT80600 offers improved efficiency and qualification for automotive Grade 2, while LM3409QMY/NOPB trades integration for design flexibility-neither is pin-compatible, and both require layout changes and firmware updates for migration.
Availability
A8501ELPTR-T is available at Aetrix Electronics and suitable for automotive infotainment, instrument cluster backlighting, and backup camera display applications requiring stable component supply despite end-of-life status.
Supply support for A8501ELPTR-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Allegro MicroSystems is a U.S.-based designer of high-performance power ICs and magnetic sensors, specializing in automotive-grade motion control and power management solutions.
The A8501 product line was engineered specifically for medium-size automotive LCD backlighting, integrating boost conversion, precision current regulation, and comprehensive fault protection in a thermally enhanced TSSOP package.
FAQ
Is A8501ELPTR-T still in production?
No, A8501ELPTR-T is a discontinued product. Allegro MicroSystems ceased production effective July 1, 2024. Samples are no longer available, and the device should not be purchased for new design applications. Aetrix Electronics maintains limited legacy stock for existing production continuity, subject to availability.
What is the recommended replacement for A8501ELPTR-T?
The officially recommended substitution is ALT80600, cited in Allegro's documentation for both existing customer transition and new applications. ALT80600 improves upon A8501ELPTR-T with lower quiescent current (1.5 µA), extended temperature range (–40°C to 125°C), and updated protection architecture, though it is not pin-compatible.
Can A8501ELPTR-T drive RGB LEDs, or is it WLED-only?
A8501ELPTR-T supports both WLED and RGB configurations. Its four independent 100 mA current sinks can drive separate red, green, blue, and white LED strings with individual dimming control via SEL1/SEL2 pin logic, enabling dynamic color mixing and white-point adjustment in automotive displays.
What thermal management is required for A8501ELPTR-T in automotive applications?
A8501ELPTR-T requires connection of its exposed thermal pad (PAD) to a large copper pour on the PCB, using star-grounded multi-point vias to PGND. With RθJA = 28°C/W on a 4-layer JEDEC board, sustained 400 mA operation at 85°C ambient demands ≥4 cm² of 2-oz copper under the pad to maintain junction temperature below 150°C.
Does A8501ELPTR-T support analog dimming in addition to PWM?
Yes, A8501ELPTR-T supports three dimming methods: (1) PWM via EN pin (100–300 Hz), (2) 4:1 analog scaling via DIM pin (low = 100%, high = 25%), and (3) continuous analog control via VTI pin using external NTC or DAC voltage-enabling precise thermal derating and smooth brightness transitions.
A8501ELPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 4
- Voltage - Supply (Min):
- 8V
- Voltage - Supply (Max):
- 21V
- Voltage - Output:
- -
- Current - Output / Channel:
- 100mA
- Frequency:
- 2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
A8501ELPTR-T FAQ
1.How can I place an order for A8501ELPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8501ELPTR-T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for A8501ELPTR-T reliable?
The price and inventory of A8501ELPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8501ELPTR-T is usually 5 days.
3.What payment methods are accepted for A8501ELPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8501ELPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8501ELPTR-T?
A8501ELPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8501ELPTR-T order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for A8501ELPTR-T?
For technical support, including A8501ELPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8501ELPTR-T requirements.
6.How does Aetrix verify that A8501ELPTR-T is sourced from the original manufacturer or authorized distributors?
All A8501ELPTR-T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that A8501ELPTR-T meets industry standards.
7.What is the process for return or replacement of A8501ELPTR-T?
All A8501ELPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8501ELPTR-T, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The A8501ELPTR-T part is unused and in its original packaging.
Return procedure for A8501ELPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A8501ELPTR-T Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
